The rapid increase in obesity and excessive abdominal/visceral fat deposition in people of the Western world, and its significant healthcare costs have motivated a search for better prevention and management strategies. Overweight as well as excessive deposition of abdominal or visceral fat is of concern since it has been linked to metabolic disturbances and increased risk for cardiovascular disease and type 2 diabetes. Despite continuing efforts to educate the public of the association of excessive fat deposition and overweight with chronic diseases, the prevalence of excessive fat deposition continues to increase. One of many reasons for this might be that most people are unable to make wilful, lifelong dietary changes.
With this growing frequency of obesity and life style-related diseases many points of intervention have been addressed. Alongside evaluation studies of popular weight loss regimens, scientific interest has also extended to secretory products shown to influence aspects of pathogenesis of diseases relating to excessive fat deposition. Here the physiology of fasting has become an issue since excessive fat deposition stems from an excess of caloric intake over expenditure.
A critical event in the fasting response is its metabolic adaptations and the liberation of fatty acids from adipose tissue governed by numerous endocrine and cellular factors. One such factor is the fasting induced adipose factor (FIAF, or PGAR for PPARγ angiopoietin related) which is a secreted lipoprotein lipase (LPL) inhibitor. LPL functions in a number of cells as the rate-limiting step for uptake of triglyceride-derived fatty acids. FIAF is a downstream target gene of both peroxisome proliferator activated receptors (PPAR)-α and -γ, the agonists of which are widely used for the treatment of type II diabetes, insulin resistance and dyslipidemia. FIAF has been reported to be highly expressed in liver and adipose tissue (Yoon et al. 2000) and interestingly plasma levels of the protein decrease on a chronic high fat diet (Kersten et al. 2000). Furthermore, Bäckhed and associates have appointed FIAF as a mediator of microbially regulated fat storage (Bäckhed et al. 2004) and shown it to be downregulated in the presence of a whole gut flora (Bäckhed et al. 2007).
Thus, in recent years, people have begun to understand the benefits of a well composed gut flora (microbiota) and the use of pro- and prebiotics are readily discussed. Use of probiotics to counteract the negative effect of the microbiota on the energy homeostasis of the host, which results in increased fat deposition, has been suggested (e.g. WO 2006/012586).
In WO 2007/043933 a study is disclosed showing that mice given probiotic bacteria have a lower storage of abdominal fat compared to mice not receiving probiotics. Gene expression studies showed that probiotic influence the expression of a cluster of genes involved in energy, fat, sugar and insulin metabolism and on satiation. However, these effects correlated with decreased food intake and studies on human subject indicate increase satiety after consumption of food with probiotics.
In production of feed, food and beverages, treatment of ingredients or end-products by high temperatures is often used in order to improve taste, texture or shelf-life. However, the use of micro-organisms for management of weight or fat deposition has mainly focused on use of live bacterial cultures, e.g. as in yoghurt cultures. The possibility of manufacturing products in which the beneficial effects of the bacteria persist despite treatment with high temperatures has never been investigated.
JP 2007 284360 provides an extract of lysed Lactobacillus for improving the lipid metabolism by activation of PPAR and in order to treat obesity. Use of the fraction as a dietary supplement is illustrated in the examples. However, the fraction is insoluble in water and there is no suggestion that the essential constituent(s) of the fraction would be heat persistent.
Accordingly, there is a need for technology allowing the use of bacterial strains with a beneficial effect on lipid metabolism in the manufacture of heat treated natural remedies, dietary supplements, food ingredients, fortificants, feeds, food or beverage products.